Fig. 3. The kinetics of the cycloaddition of oxoTCO 3 with water-soluble 3,6-dipyridyl-s-tetrazine-mono-succinamic acid 10 in PBS buffer (pH 7.4). Second order rate constants (k2) were determined with a stopped-flow spectrophotometer under pseudo-first order conditions using ca. 10–30 equivalents of oxoTCO 3 (2.2 : 1 dr) by monitoring the decrease in tetrazine absorbance at 325 nm.
